Web App: Slicing Emails

How to upload an email design, slice it into sections, and push a ready-to-send template to Klaviyo.

Step 1: Upload Your Email Design

Drag and drop your full-length email design image into Grotto Slice, or click to browse your files. The image should be a single, full-length export of your entire email (JPEG or PNG, 1200px wide recommended).

Step 2: AI Slice

Click AI Slice to automatically detect the best cut points in your design. The algorithm analyzes background colors, content boundaries, and spacing to find clean break points between sections.

After slicing, you can fine-tune the results:

Adjusting Slice Lines

  • Move a slice line - click and drag any slice line up or down to reposition it
  • Add a new slice line - click on the image where you want a new cut
  • Delete a slice line - double-click on the line to remove it

Step 3: AI Alt Text

Click AI Alt Text to generate descriptive alt text for each section. Alt text improves accessibility for screen readers and can help with email deliverability. You can edit the generated text for any section before uploading.

Click on each sliced section to set its click-through URL. When a recipient clicks that section in the email, they will be taken to the URL you set. Your brand's default website URL is pre-filled, and you can customize each section individually.

Preview Text

Enter your email preview text in the Preview Text field. This is the short snippet that appears next to the subject line in a recipient's inbox before they open the email.

Template Name

The template name defaults to your image file name. You can edit it before uploading - this will be the name of the template in your Klaviyo account, so use something descriptive like "Summer Sale - June 2025".

Step 5: Upload to Klaviyo

Click Upload Klaviyo Template to push the finished template to your Klaviyo account. Grotto Slice compresses the images, packages the HTML, and creates a drag-and-drop template in Klaviyo that is ready to use in any campaign or flow.

Working with Individual Sections

With the Section Selection tool active, you can right-click on any sliced section to access additional options:

  • Upload to Klaviyo - upload that single section image to your Klaviyo account's media folder
  • Download to device - save the cropped section image to your computer

This is especially useful when your designer updates a single section of the email after you have already uploaded the full template to Klaviyo. Instead of re-uploading the entire email, you can:

  1. Upload the updated design image to Grotto Slice (your previous slice lines, alt text, and link addresses are preserved automatically)
  2. Right-click the section that changed and select "Upload to Klaviyo" to send just that image to your Klaviyo media folder
  3. In Klaviyo, open your existing template and swap the old section image for the updated one

Email History

Every email you upload is saved to your Email History page, accessible from the main navigation. From here you can:

  • View all previously uploaded templates
  • See the date, template name, and section count for each upload
  • Re-open a past upload to reference your slice layout and settings

Email History keeps a record of everything your team has uploaded, making it easy to find and reference past designs.

Using in Klaviyo

Once your template is uploaded, see our Using Templates in Klaviyo guide for a full walkthrough on editing, adding your footer, and sending campaigns.

Frequently Asked Questions

What image formats can I upload?

JPEG and PNG files are supported. We recommend exporting your email design at 1200px wide for the best results.

How does AI Slice decide where to cut?

The algorithm detects background color changes, content boundaries, and quiet zones in your design to find the cleanest possible cut points between sections.

Can I undo changes to slice lines?

You can re-run AI Slice at any time to reset all slice lines back to the auto-detected positions.

What is AI Alt Text?

AI Alt Text uses AI to generate descriptive alt text for each section of your email. This improves accessibility for screen readers and helps with email deliverability.

What happens if I upload a template with the same name?

Grotto Slice will update the existing template in Klaviyo with the new content. This makes it easy to iterate on designs without creating duplicate templates.

Where can I find my uploaded templates in Klaviyo?

After uploading, your template appears in Klaviyo under Email Templates. You can use it in any campaign or flow.